I had a problem. I tried to use join fetch to solve the problem of pulling subscriptions together with customers and not worrying about grouping them. But it's important for the design to be efficient. Because we're working on a million customers, two million subscriptions and 400,000 books. I used Pageable. Should I use join fetch?

I tried to use join fetch to solve the problem of pulling subscriptions together with customers and not worrying about grouping them. But it's important for the design to be efficient. Because we're working on a million customers, two million subscriptions and 400,000 books. I used Pageable. Should I use join fetch?